<template>
  <div class="hello">
    <h2>商品ID:{{id}}</h2>
    <button @click="getNumber">获取数量</button>
  </div>
</template>

<script>
export default {
  name: 'child',
  data () {
    return {
      num:0
    }
  },
  methods:{
    getNumber(){
      this.num = 100;
      this.$emit("getNumber",this.num);
    }
  },
  mounted(){
     
      this.getNumber();
  },
  props:{
    id:{
        type:Number,
        default:0
    }
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
h1, h2 {
  font-weight: normal;
}
ul {
  list-style-type: none;
  padding: 0;
}
li {
  display: inline-block;
  margin: 0 10px;
}
a {
  color: #42b983;
}
</style>
